Cable overload switch



Sept. 21, 1954 w. E. GREEN CABLE OVERLOAD SWITCH Filed Oct. 8, 1949 Z@ afm f L l 5154"? 50 f4? um 5? Patented Sept. 2l, 1954 UNITED .STATES PATENT AOFFICE 2,689,890 CABLE OVERLOAD SWITCH Willis E. Green, Spokane, Wash.

Application October 8, 1949, Serial No. 120,306

2 Claims. l

This invention relates to a stage or scaffold and it is one object of the invention to provide a stage which is suspended from an overhead support on a single cable and consists of a scaffold or chair of such size that it will accommodate one person and is raised by winding its cable upon a drum mounted in the stage and Voperated by means of a motor.

Another object of the invention is to provide a stage having a frame which is formed of metal tubes or pipes and has at its rear 'or other side an arm which is braced against transverse bending and carries pulleys about which is trained a suspension cable which has its lower end wound about a drum carried by the shaft of a motor which is mounted upon the floor of the stage where it will be out of the way.

Another object of the invention is to provide a stage having a frame provided with guards which will prevent a workman from falling out of the stage or chair and also provided with arms which hold the stage spaced from a wall, smoke stack, or the like and carry rollers for bearing against the wall or smoke stack and allowing the stage to be easily shifted vertically along the same.

Another object of the invention is to provide a switch so mounted in relation to a guide pulley for the cable that when the stage is overloaded the switch will be opened by pull upon the cable and the current shut off and raising of the stage prevented. Therefore danger of the cable being overloaded and the cable breaking will be eliminated.

Another object of the invention is to provide a stage which is of light weight but very strong as it is formed of metal tubes or pipes andcouplings for the pipes.

A practical embodiment of the inventiony .is illustrated in the accompanying drawings where- Fig. 1 is a side elevation of the improved stage.

Fig. 2 is a top plan view thereof.

Fig, 3 is a fragmentary sectional View upon an enlarged scale taken along the line 3--3 of Figure l.

Fig. 4 is an enlarged fragmentary view showing the switch-opening pulley and associated parts.

This improved stageV or scaffold is intended for use by one workman instead of two or more and is suspended from an overhead support by a single cablel instead of consisting of an elongated platform or stage having a suspending cable at each end. The frame 2 of this stage is formed of metal tubes or pipes and has side walls 3 and an arm 4 which extends upwardly at its back and is curved forwardly so that it overhangs the frame, as shown in Figures l and 2. The side walls and the arm are'formed from a single length of tubing which is bent midway its length to form the arm and has its end portions bent to form the side walls. Referring to Figure 2 it will be seen that the arm 4 has side bars 5 which are joined at their front ends by a bridge or head B. These side bars extend in spaced parallel relation to each other to a point adjacent the back of the frame and are then spread apart and extend downwardly in diverging relation to each other to lower rear corners of the side walls 3. The arm is curved longitudinally for its entire length, and at the level of upper ends of the side walls the diverging portions of its bars carry couplings 'I having forwardly projecting sockets 0. Close to their lower ends the bars carry couplings 9 having sockets I0 eX- tending upwardly at a forward incline from their front side portions. At lower `endsl of the diverging portions of the side bars of the arm Il the tube has its end portions bent forwardly to form the lower, bars II of the side walls 3, then upwardly to form the vertical front bars I2, and then rearwardly to form the upper bars or rails of the side walls. These upper bars or rails i3 have their rear ends fitted into the arms or sockets 8 of the couplings 1 and since bolts I4 'are passed through the couplings and their sockets the couplings will be firmly held in their proper positions upon the bars 5 and rear ends of the upper rails I3 firmly held in the sockets. Couplings I5 are mounted upon the upper rails or bars I3 in spaced relation to rear ends thereof and have inwardly projecting sockets I6 in which are secured the Aends of a rear cross bar or spacer Il. There has also been provided a front cross bar or spacer I8 and the side walls 3 of the frame will therefore be retained in predetermined spaced and parallel relation to each other.

Braces I9 which are formed of tubing extend vertically at opposite sides of the rear portion of the frame and have their lower ends mounted in the sockets I0 of the couplings 9 and their upper portions bent forwardly and towards the front end of the arm 4 where they are mounted through sockets 20 at opposite sides of a bracket 2 I. This bracket 2I spans space between front end portions of the bars 5 and along its 'side portions is formed with sleeves '22 through which the bars 5 pass. Bolts or equivalent fasteners 23 secure the braces I9 and the bars 5 through the socketsV 20 and the sleeves 22 of the bracket 2|. It will thus be seen that the entire frame, with the eX- ception of the spacers I1 and I8 and the braces I9, is formed from a single length of metal tubing which is of light weight but very strong. Lower portions of the braces I9 form vertically disposed rear bars for the side walls and between these rear bars and the front bars I 2 of the side walls are mounted midpails or bars 24 which serve as supports for a seat 25 upon which a workman may sit, or the workman may use this seat as a shelf and place cans or paint or other material thereon.

The cable I is wound uponra drum 26 carried by the shaft of an electric motor 21 which is supported upon the floor 20l of the stage, and referring to Figures 1 and 2 it will be seen that this oor is formed of thick sheet metal which has its side portions rolled about the lower bars of the side walls 3 of the frame. The cable is carried upwardly from thedrum or winch and engaged with a pulley 29 carried by a support 29 which is disposed between and secured about the side bars 5 of the arm 4 at the junction of the parallel portions of these bars with the downwardly diverging portions thereof. From the pulley 28 the cable extends forwardly at an upward incline and after being engaged with a pulley 30 is passed upwardly through the front end of the arm 4 so that it may be connected with an overhead support and serve to suspend the stage therefrom. The motor is of the reversing type so that the drum may be turned in one direction to wind the cable thereon and raise the stage or in an opposite direction to unwind the cable and lower the stage.

Referring to Figure 4 it will be seen that the pulley is rotatably mounted between the forks 3| of a lever 32. The lever extends longitudinally of the front end portion of the arm 4 in downwardly spaced relation thereto and at its rear end is formed with a bearing 33 to receive a pin on shaft 34 carried by ears 35 which project downwardly from the rear end of a block 36 forming the central portion of bracket 2|. A socket 31 is formed in the under face of the block 36 to receive the upper portion of a spring 38 which has its lower convolutions engaged about a stud 39 projecting upwardly from the lever 32, the spring serving to urge the lever downwardly and maintaining the pulley wheel 30 in engagement with the cable. A switch 40 is secured against the under face of the block 36 by screws 4| and the button 42 of this switch projects downwardly therefrom and bears against the upper face of the lever 32 back of the spring. When the stage is subjected to a load which the cable can safely carry, the spring prevents the lever 32 from moving upwardly beyond the position shown in Figure 4 but if the cage is overloaded the lever will be swung upwardly and the spring compressed suinciently to allow the push button 42 to be forced upwardly and the switch opened. The circuit through the motor will then be broken and the drum can not be turned. 'Therefore the stage can not be raised until the load has been lightened and danger of workmen being injured or killed by the cable being broken by an overload is avoided.

When the stage is in use it is desired to have it held in spaced relation to the wall or smoke stack to be painted or repaired. In order to do so there have been provided castors 43` which project forwardly from the side walls 3 of the frame 2. These castors are at front ends of bars 44 which are slidably mounted through heads 45 at outer ends of arms 46 slidably carried by a cross bar 41 disposed across the front of the frame and welded to the front bars .|2 of its side walls. Longitudinally spaced openings 48 are formed in the bar 46 and opposed openings 49 are formed in front and rear walls of the hollow cross' bar 41 so that the bars 46 may be shifted longitudinally to cause them to project from opposite sides of the frame a desired distance and the pins 50 then passed through registering openings 48 and 49 and secure the bars in the adjusted position. The bars 44 are also formed with longitudinally spaced openings 5| and the heads 45 of the bars 46 formed with openings so that the bars 46 may be shifted longitudinally through the heads and pins 52 then passed through registering openings to secure the bars in adjusted positions and cause the castors 43 to be spaced forwardly from the frame a sufficient distance to allow the stage to be moved along a wall or smoke stack without scraping or striking obstructions. The stems 53 of the castors pass through squared openings at front ends of the hollow heads 54 of the bars 44 and are urged rearwardly by springs 55 and as the front end portions 56 of the stems are squared and fit snugly in the squared openings of the heads the castors will be prevented from turning in these openings. Therefore the castors may have their rollers 51 disposed in position for rolling vertically or the castors drawn forwardly to move the squared portions of their stems out of the openings in the heads and the castors then turned to dispose their rollers in position for horizontal rolling movement, the castors then being released so that the springs return them to the normal position in which the squared portions of the stems hold them in the adjusted position.

Having thus described the invention, what is claimed is:

l. A circuit breaker for the circuit of an electric motor driven Winch and cable system, comprising a frame having an arm extending upwardly therefrom in overhanging relation thereto, cable-engaging pulleys carried by said arm, one pulley rotatably supported under the overhanging portion of the arm by a bracket pivotally connected with the arm and constituting a switch-operating lever, a normally closed switch for the motor mounted upon the arm over said lever and having a downwardly projecting switchbutton engaged by the lever and movable upwardly by pressure of the lever to open the switch when the lever is swung upwardly beyond a predetermined position by action of the portion of the cable engaging the pulley carried by the lever when the cable is subjected to abnormal pull, and a spring between the lever and the overhanging portion of the arm yieldably preventing upward movement of the lever into position to open the switch.

2. The structure of claim 1 wherein the overhanging portion of the arm is formed with a seat in its under surface disposed over a spring seat upon the lever, the spring being a helical spring disposed vertically and having its upper end mounted in the spring seat of the arm and its lower end engaged with the spring seat of the lever.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date Re. 19,024 McNeil Dec. 12, 1933 177,477 Crockett May 16, 1876 595,992 Cody Dec. 21, 1897 842,331 Palmer Jan. 29, 1907 1,003,913 Kilcoyne Sept. 19, 1911 1,433,079 Jett Oct. 24, 1922 1,546,971 Denniston July 21, 1925 1,640,673 Scheinfeld Aug. 30, 1927 1,703,743 Mair Feb, 26, 1929 1,839,579 Murray Jan. 5, 1932 2,008,081 Mousette July 16, 1935 2,178,956 Dyer Nov. 7, 1939 2,396,127 Riblet Mar. 5, 1946 2,445,228 Le Tourneau July 13, 1948 2,573,997 Souza Nov. 6, 1951 FOREIGN PATENTS Number Country Date 56,292 Switzerland Apr. 15, 1912 

